Re: [gtkmm] adding a widget to a container

[cedric <cedric probesys com>]

Ainsley Pereira a e'crit :

> Hi again,
>
> I'm not quite sure I follow your description, but there are a couple of
> things I can point at for you to investigate further:
>
> On Mon, May 03, 2004 at 06:00:26PM +0200, cedric wrote:
>  
>
> > so to do this, i ve 2 ptr declared in my Plugin.hh file
> >   static Gtk::HBox *toolBarModContainer_ptr;
> >   static Gtk::Toolbar *toolBarModDisplayed_ptr;
> >    
>
> If you declare a static, it's visible only to that translation unit
> (think of this as the .cc file and all the files it #includes). Putting
> a static in a .h file is almost always the wrong thing to do - if two
> .cc files include it, you end up with TWO copies of the variable, both
> with the same name, but not the same variable. If you're including
> Plugin.hh from two different .cc files, and setting the variable in one,
> but using it in the other, you're not setting the same variable.
>
>  
ah ok! someone (not on this ml) told me to put the "static" in the .hh ...
i have several files which herits from Plugin.hh, this can be the problem!
but it s strange that in some cases it works well (when i just hide the 
widget pointed by the pointers) and other times not (when i add a 
toolbar to the container pointed), and this in the same file.
Anyway, to have those pointer accessible and unique in all the files 
which herits from Plugin.hh, what should i do? just put off the "static" 
keyword? if i do this, i have a compilation error saying that the 
pointers are not static members of the Plugin class (if i leave a 
declaration of the pointers like "Plugin::Gtk::HBox 
*toolBarModContainer_ptr" in the loadplugin.cc file which herits from 
Plugin.hh), and/or saying the pinters are not declared (if i remove 
these declarations).

> (General hint: Always initialise pointers at declaration. If you can't
> give them their final value yet, initialise them to 0. If you do that
> here, you can at least verify whether what I've described above is
> what's happening in your code, by checking if it's still 0 before you
> use it.)
>  
ok, i ll remember to do that in the future!
but i can t initialise it in the .hh files :p

>  
>
> > when i put this, it provoques a segfault:
> >    
>
> Do you mean a segfault here? or a link error?
>  
it s a seg fault, but there is a link error instead if declare 
toolbarmod as static.

thanks,

cedric